Originally, being anonymous online was how everyone participated in the great meritocracy that was the early Internet. Someone who did clever or funny things, created useful tools, or solved problems, was judged solely on that, and not based on their age, gender, or appearance.
Today this seems even more important as everything someone says, and everything in our lives becomes a matter of public record. It is harder than ever for people to shed a less than great past, overcome stereotypes, or express dissidence without exposing themselves to persecution.
There is a flip side of bad actors who you anonymity as a mechanism to be nasty with no consequences. This grieves me a great deal, because I value my anonymity for a multitude of reasons, and have tried to conduct myself in a way that speaks for itself, but their behavior makes defending anonymity more difficult.
I hope as Nostr continues to develop more and better tools for users to curate their feed that the value proposition of online anonymity becomes clearer.